Breather and drain



Dec. 5, 1967 M. cs. ZAVERTNIK ET AL 3,356,255

BREATHER AND DRAIN Filed Aug. 3 1965 82 8 //v \/ENTO P5.

MARSHALL 6. ZAVEQTN/K) 0/? 1 10 A. WA YN E av United States Patent 3,356,255 BREATHER AND DRAIN Marshall G. Zavertnik, Manchester, and David A. Wayne, Rolla, Mo., assignors to Killark Electric Manufacturing Company, St. Louis, Mo., a corporation of Missouri Filed Aug. 2, 1965, Ser. No. 476,569 4 Claims. (Cl. 220-88) This invention relates to a device for use in a hazardous location as a breather or a drain to permit gases or liquids to escape through it while blocking passage of a flame. The device is threaded into a Wall, usually of the kind which forms part of an enclosure for electrical apparatus. In particular, the invention relates to a breather or drain device which allows gases to escape through it but which chokes a flame and which acts to relieve and equalize pressure such as might be caused by the explosion or combustion of gases.

The embodiments shown concern a device that may be used as a breather to permit gases to escape from the hazardous location or as a drain to permit draining of condensation liquids. Each modification provides full protection against the passage of any flame through the device in the event of the igniting of gases within the hazardous location area. In each embodiment, the device will function as a breather without exposing openings to water from a driving rain and, with simple and inexpensive modification, will function as a drain to let all moisture drain from an enclosure.

Generally, the device comprises a body with a recess or well in it for receiving a flame arrester slug. The slug is formed of sintered bronze or other metal or material that is highly porous. The porosity of the slug gives it many small tortuous passageways that permit gas or liquid" to flow through them, but are sufficiently narrow and long to prevent the passage of a flame. The size and length of the tortuous paths may vary. Relatively longer paths may be accompanied by larger diameters. Tests will indicate whether a particular slug design successfully quenches a flame and gives proper breather performance.

The principal object of this invention is to provide an economical breather or drain for use in hazardous locations, which is compact and easy to install, and which prevents passage of a flame.

Another object of the invention is to provide a device, which, in one form, requires only slight modification in construction to change it from a breather to a drain and, in another form, can be changed from a breather to a drain by simple replacement of a snap-on cap. Another object is toprovide such a device wherein the breather is connected into a side wall without exposing elements to driving rains and wherein the slight modification permits installation of the device in a bottom wall for acting as a drain.

An important object of the invention is to provide a device for attaching through a side or bottom wall of an enclosure to act as a breather or drain wherein the construction pe'rmits the device to relieve pressure in or outside the enclosure, permitting reduction in wall thickness of the enclosure.

Another object is to provide a breather or drain device for use in hazardous locations which comprises a body with a recess for receiving a porous slug, wherein, upon the occurrence of an explosion, the slug is self-seating in the recess to force all gases and vapors through the slug which, in turn, blocks the passage of a flame.

Other objects and advantages will be apparent from the specification and drawing.

In the drawing:

FIGURE 1 is a plan view of the head of one form of breather incorporating the principles of this invention;

3,356,255 Patented Dec. 5, 1967 FIGURE 2 is a side elevation view of the breather of FIGURE 1;

FIGURE 3 is an enlarged view in longitudinal medial section through the breather, as mounted in a wall of an enclosure;

FIGURE 4 is a plan view of the head of a drain which is similar to the breather of FIGURE 1;

FIGURE 5 is a side elevation view of the drain of FIGURE 4;

FIGURE 6 is a view in longitudinal medial section on an enlarged scale through the drain and showing the drain mounted in a bottom wall of an enclosure;

FIGURE 7 is a plan view of the head and cap of another form of breather;

FIGURE 8 is a side elevation view of the breather of FIGURE 7;

FIGURE 9 is an enlarged view in longitudinal medial section through the breather of FIGURE 7 and showing the breather mounted in a wall;

FIGURE 10 is a plan view of the head and cap of a drain similar to the breather of FIGURE 7;

FIGURE 11 is a side elevation view of the drain of FIGURE 10; and

FIGURE 12 is an enlarged view in longitudinal medial section through the drain of FIGURE 10 and showing the drain mounted in a wall.

Referring now to the drawing, the breather device 20, shown in FIGURES 1 and 2, comprises a body 21 having an externally threaded portion 22, an outwardly tapered section 23 leading to a larger diameter cylindrical section 24, and a head 25. The body is about 1% inches long. There is a recess 26 of about inch length and inch diameter in the threaded portion 22 of the body and a smaller diameter recess 27 communicating with the recess 26. Several small passages 28 lead from the tapered section 23 to the side wall definingthe smaller diameter recess 27. The passages are at about a 45 angle to the longitudinal axis of the body. Each passage is inch in diameter and about inch long.

A slug 29 fits within the reces 26. The slug 29 has an end 30 that bears against the shoulder between the recesses 26 and 27 and in the opposite end 31. The end 32 of the threaded section 22 is rolled or turned over and inwardly to hold the slug 29 in place. The slug 29 has inner wells 33 and 34 in its opposite end. The wells 33 and 34 increase the surface area exposed to the gases which are to escape through it.

Preferably, the slug 29 is made of sintered bronze, but it may be made from another metal or of ceramic or plastic, or any other highly porous material. The material must be something that will permit air or'gas or liquid to flow through it, but will stop a flame. In other words, the sintered bronze slug 29 provides a large number of small diameter elongated and tortuous passageways for the gases or liquids, and these small diameter long tortuous passageways will not pass a flame.

As FIGURE 3 shows, there is a wall W which forms a side wall of an enclosure H, such as one which may contain electrical apparatus in a hazardous area or vicinity where explosive and combustible gases may develop. The breather device 20 threads through the wall and permits gases to escape. These gases pass through the slug 29 and into the recess 27 whence they can pass outwardly through the several passages 28 or the gases pass in the opposite direction.

As FIGURE 3 shows, the openings 28 are not directly exposed to driving rains. Hence, although these openings satisfy the breather function, they do not permit rain to enter the body 21.

A drain device 40 is shown in FIGURES 4, 5, and 6. The drain device 40 is similar to the breather device 20 and has a body 41 comprising an externally threaded portion 42, an outwardly tapered portion 43, a larger diameter cylindrical portion 44, and a head 45. There is a recess 46 in the externally threaded section 42 and a smaller diameter recess 47 joined to the recess 46 by a shoulder 48. A plurality of passages 49 extend through the head 45 into communication with the small diameter recess 47. A slug 29 as previously described is positioned within the recess 46, and the end 50 of the threaded section 42 is turned or rolled over and inwardly to hold the slug 29 in place.

FIGURE 6 shows how the drain device 40 is mounted in the bottom wall W1 of a housing or other enclosure H of electrical apparatus in a hazardous location with the head 45 extending directly downwardly. Thus mounted, the drain device 40 can permit passage of liquids from Within the area H through the sintered bronze slug 29 to the recess 47 and out the passages 49. However, as before, no flame can pass through the slug 29. Since the device 40 is mounted in a bottom wall W, as shown, rain cannot enter the openings 49 and damage electrical apparatus within the enclosure H.

A comparison of the device 20 shown in FIGURES 1-3 with the device shown in FIGURES 4-6 indicates that these devices are identical and can be made using identical apparatus except for the passages 28 and the passages 49. These are drilled according to the intended function of the device as a breather or a drain.

FIGURES 7, 8, and 9 show a modified form of breather device 60. The device 60 has a body 61 with an externally threaded section 62, a head 63, and an extension 64 beyond the head 63. There is a passage through the body 61 including a relatively large diameter portion 66 and a slightly smaller diameter portion 67. A shoulder 69 joins the passage 66 to the passage 67. A slug as previously described fits within the passage 66, and is held against the shoulder 69 by a rolled-over end bead 70.

There is an annular groove 71 in the extension 64. A cap member 73 has individual legs 74 with beads 75 sprung into the annular groove 71. There are breather spaces 76 between the legs 74.

When the device 60 is mounted in the side wall W-2 of an enclosure H for electrical apparatus located in a hazardous area H, gases can pass through the slug 29 into the passage 67 and through the spaces 76 bet-ween the legs 74. Again, a flame cannot pass through the slug 29. The cap 73 protects the pores of the slug 29 from paint which might otherwise close the pores, and from driving rain which might damage apparatus in the enclosure H.

The drain 80 shown in FIGURES l0, l1 and 12 is very similar to the breather drain 60 and, therefore, for identical parts, numbers have been repeated; these parts will not be redescribed. The additional structure for the drain 80 is that it has a cap 81 like the cap 73, but with a plurality of holes 82 through it. When the device 80 is mounted in the bottom wall W-3 of an enclosure H, liquids can pass through the slug 29 and the passage 67 and out through the holes 82. The cap 81 has legs 83 with beads 84 which snap onto the annular groove 71.

The cap 81 protects the slug and the enclosure from outside environment, such as rain, while permitting air or gases to pass freely in and out of the enclosure. The

4 caps 73 and 81 also prevent inadvertent sealing of the tortuous passageways in the slug 29 by careless application of paint to the wall W-2 or W-3.

The devices 60 and are identical except for the provision of holes 82 in the cap 81. Hence, tooling for the body 61 is the same for both devices. Also, the devices 60 and 80 are interchangeable upon simple change of the caps 73 and 81.

Some features may be noted about all the embodiments shown. As well as acting as breathers and drains, the devices can function to relieve pressure, such as that which might result from an explosion in the hazardous area. This pressure relief function permits reduction in the required thickness of the enclosure wall W. Usually, the appearance of a flame is accompanied by an increase in pressure. The slug 29 is self-seating against the shoulder, such as the shoulder 69 in FIGURE 9, thus further assuring that the gases, etc., will go through the pores in the slug.

Various changes and modifications may be made withing the purview of this invention as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims appended thereto.

What is claimed is:

1. A breather device comprising a body having external threads for threading into a wall, a head on one end of the body, a recess in the opposite end of the body, a unitary porous slug in the recess, stop means to hold the slug within the recess and against which the slug seats under explosive pressures, the pores in the slug providing a plurality of long and narrow tortuous passageways capable of passing gases but not flame through them, the slug having an end facing the head and an end opposite the head of the body, a recess in each end of the slug to increase the surface areas by which gases can pass to and from the slug, and a plurality of passages communicating with the recess and opening through the body adjacent the head thereof.

2. The device of claim 1 wherein the slug is sintered bronze.

3. The device of claim 1 wherein the head comprises a cap removably fastened to the body, the passage means comprising openings through the cap.

4. The device of claim 3 wherein the cap has individual legs separated by slots, and the slots constitute the openings.

References Cited UNITED STATES PATENTS 1,007,828 11/1911 Webb 22088 1,011,395 12/1911 Ziller 22088 1,350,109 8/ 1920 Nystrom 22044 1,579,141 3/1926 Pierce 22089 1,940,601 12/ 1933 McCrery et al. 22044 2,298,938 10/ 1942 Grifiin et al. 220-44 2,323,146 5/1943 Manney 22044 2,394,333 2/ 1946 Schneider 220-44 2,425,609 8/1947 Fink 22044 2,618,540 11/1952 Teti 22088 RAPHAEL H. SCHWARTZ, Primary Examiner. 

1. A BREATHER DEVICE COMPRISING A BODY HAVING EXTERNAL THREADS FOR THREADING INTO A WALL, A HEAD ON ONE END OF THE BODY, A RECESS IN THE OPPOSITE END OF THE BODY, A UNITARY POROUS SLUG IN THE RECESS, STOP MEANS TO HOLD THE SLUG WITHIN THE RECESS AND AGAINST WHICH THE SLUG SEATS UNDER EXPLOSIVE PRESSURES, THE PORES IN THE SLUG PROVIDING A PLURALITY OF LONG AND NARROW TORTUOUS PASSAGEWAYS CAPABLE OF PASSING GASES BUT NOT FLAME THROUGH THEM, THE SLUG HAVING AN END FACING THE HEAD AND AN END OPPOSITE THE HEAD OF THE BODY, A RECESS IN EACH END OF THE SLUG TO INCREASE THE SURFACE AREAS BY WHICH GASES CAN PASS TO AND FROM THE SLUG, AND A PLURALITY OF PASSAGE COMMUNICATING WITH THE RECESS AND OPENING THROUGH THE BODY ADJACENT THE HEAD THEREOF. 